The Lebanon express. (Lebanon, Linn County, Or.) 1887-1898, 1887-06-17
COLLIERY EXPLOSIONS.
Efforts Which Have Been Made
to Prevent Them.
The "Davy" Lamp and Fire Damp-Coal
Dust Firing 10 Give
Place to safer Methods of
Explosions.

The atmosphere of every coal-mine
probably contains more on less marsh
gas. although in some the amount Is 50
very small that the mir within them
could never become explosive under or
dinary conditions Of working. There
Is no doubt that gas frequently escapes
detection owing Ia the imperfection Of
the means employed for its recognition.
II present in certain proportions the
marsh gas is revealed by the clonga-
ton Of the flame Of the safety-lamp. or
by the appearance Of what is
known as "A leap" upon the flame.
An experienced eye can determine prct-
ty accurately the relative amount of
the fire-lamp from the size and character
of the cap upon properly trimmed
flame; but the test altogether fails when
the proportion of gas falls below two
per cent. This amount. small as il may
seem, may, under certain circun-
stances. prove highly dangerous. The
mine-manager and the ''iiremenn re-
quire to use some more delicate method
of detecting small quantities of fire
damp than that usually employed. For
tunately such methods are not unknown.
MIR. Livcing has devised very ingeni-
ous Indicator. by which the existence
Of marsh gas can be detected and its
amount estimated even when the guam
tity Is as low rs quarter per cent.
Two precisely similar pieces of thin
platinum wire are simultaneously
heated to bright redness by the action
of small magneto-eleetrie machine
worked by hand. One of the wires is
contained in small tube filed with pure
air; the other can be surrounded at will.
aud in minute or two. with air
from any part of the mine. II fire
damp is present it burns round the hot
wire, which is thereby increased i'm
temperature and emits n more brilliant
light. BY comparing the intensities of
the light emitted by the two wires by
the aid Of very simple photometric
arrangement the percentage amount of
tsre-damp present may be Mt once de-
termined. The apparatus is portable
and easily worked. and is well adapted
for use under ground.
Seventy years have elapsed since Sir
Humphrey Davy invented the Safety
lamp which is associated with his name
II is almost impossible TO overestimate
the influence of that invention in the
development of eoal-mining- the de-
velopment. indeed. of our national
prosperity. 1t has unquestionably
saved thousands of lives, and has en-
abled millions of tons of coal to be
I :
sibly have been won.
IL is related that when Mr.. Buddle,
whose name is well known i'm the
history of coal-mining for the
improvements he introduced into
tie sy1tem II ventilating collieries.
took down one of the first Davy lamps
into fiery pit aud beheld the fire-damp
"cap" playing round the light and ap-
lparently imprisoned within the wire
gauze cylinder. he exclaimed exult-
Iingly: "At last we have subdued this
monster
Not year passes, however, without
the monster showing us that he is
still very far from subjection; and.
strange to say, the Davy lamp itself
aud the very system of ventilation
which we owe To Mr.. Buddle, rs de-
veloped in these later times, have con-
spired to aid the monster in his work
of havoc and disaster.
How this has come about may be
told in very few words. When the
lamp was first introduced the ventilat-
ling currents in mines seldom exceeded q
velocity of three hundred feet pei
minute in the air-ways, and they were
usually very feeble in the working
J places. Nowadays the enormous fans
and other mechanical ventilators which
are employed cause the air to travel al
velocities approaching two thousand
feet per minute in the aIr-ways, and cur
rents of more than four hundred feet pei
: minute are not unfrequently met witt
at the working places. Under these
: conditions the Davy lamp and, in {
lesser degree, two other well-knowr
forms of safety lamp-the Clanny ant
the Stephenson lamps-become abso
lutely unsafe in an explosive atmos
lphere. Indeed, the ordinary .Dav,
lamp will ignite gas outside it if ex
Iposed to an explosive current travelin;
, 1t less than four hundred feet per min
L ute
The Royal Commissioners, as far bacl
= rs 1880. directed the attention of til
Home Secretary to the fact ''that til
employment of the ordinary Davy lam
= without shield of metal or of glass, i
an explosive mixture, when the ri
currents exceed six feet per second,
attended with risk of accident almos
amounting to certainty" Indeed
merely attempting to blow out th